Anomalous Epithelial Variations and Ectopic Inflammatory Response in Chronic Obstructive Pulmonary Disease.

Phenotypic alterations in the lung epithelium have been widely implicated in chronic obstructive pulmonary disease (COPD) pathogenesis, but the precise mechanisms orchestrating this persistent inflammatory process remain unknown because of the complexity of lung parenchymal and mesenchymal architecture. To identify cell type-specific mechanisms and cell-cell interactions among the multiple lung resident cell types and inflammatory cells that contribute to COPD progression, we profiled 57,918 cells from lungs of patients with COPD, smokers without COPD, and never-smokers using single-cell RNA sequencing technology. We predicted pseudotime of cell differentiation and cell-to-cell interaction networks in COPD. Although epithelial components in never-smokers were relatively uniform, smoker groups represent extensive heterogeneity in epithelial cells, particularly in alveolar type 2 (AT2) clusters. Among AT2 cells, which are generally regarded as alveolar progenitors, we identified a unique subset that increased in patients with COPD and specifically expressed a series of chemokines including CXCL1 and CXCL8. A trajectory analysis revealed that the inflammatory AT2 cell subpopulation followed a unique differentiation path, and a prediction model of cell-to-cell interactions inferred significantly increased intercellular networks of inflammatory AT2 cells. Our results identify previously unidentified cell subsets and provide an insight into the biological and clinical characteristics of COPD pathogenesis.

Selective targeting of KRAS-driven lung tumorigenesis via unresolved ER stress.

Lung cancer with oncogenic KRAS makes up a significant proportion of lung cancers and is accompanied by a poor prognosis. Recent advances in understanding the molecular pathogenesis of lung cancer with oncogenic KRAS have enabled the development of drugs, yet mutated KRAS remains undruggable. We performed small-molecule library screening and identified verteporfin, a yes-associated protein 1 (YAP1) inhibitor; verteporfin treatment markedly reduced cell viability in KRAS-mutant lung cancer cells in vitro and suppressed KRAS-driven lung tumorigenesis in vivo. Comparative functional analysis of verteporfin treatment and YAP1 knockdown with siRNA revealed that the cytotoxic effect of verteporfin was at least partially independent of YAP1 inhibition. A whole-transcriptome approach revealed the distinct expression profiles in KRAS-mutant lung cancer cells between verteporfin treatment and YAP1 knockdown and identified the selective involvement of the ER stress pathway in the effects of verteporfin treatment in KRAS-mutant lung cancer, leading to apoptotic cell death. These data provide novel insight to uncover vulnerabilities in KRAS-driven lung tumorigenesis.

Diffuse pleural thickening and thoracic contraction: An indistinguishable case from malignant pleural mesothelioma.

The differential diagnosis of reactive mesothelial hyperplasia and mesothelioma is difficult. We present a rare case of diffuse pleural thickening with thoracic contraction that was indistinguishable from mesothelioma. A 66-year-old woman with no history of asbestos exposure visited our hospital with a complaint of dyspnea. The clinical findings included circumferential pleural thickening on chest computed tomography image and a high concentration of hyaluronic acid in the pleural fluid. Pleural biopsies obtained by thoracoscopy under local anesthesia were pathologically consistent with mesothelioma, but the patient refused to take any kind of mesothelioma treatments. Four months later, she consented to a surgical pleural biopsy under general anesthesia to obtain larger tissue samples, which included typical proliferating polygonal cells positive for CAM5.2, calretinin, WT-1, D2-40, CK5/6, epithelial membrane antigen, and glucose transporter-1 and negative for carcinoembryonic antigen, BerEP4, and MOC31. The analysis was consistent with diagnosis of epithelioid mesothelioma. Fluorescence in situ hybridization, however, showed the presence of p16 gene, and the expression of BRCA1-associated protein-1 was detected by immunohistochemistry. Our final diagnosis was diffuse pleural thickening unrelated to asbestos exposure. Differential diagnosis of diffuse pleural thickening and malignant mesothelioma is thus difficult and routine immunohistochemical examinations are often insufficient for accurate diagnosis. Multiple diagnostic methods are required for correct diagnosis in a clinically marginal case.

Quercetin Inhibits Lef1 and Resensitizes Docetaxel-Resistant Breast Cancer Cells.

Drug resistance is a major problem for breast cancer patients. Docetaxel is an anti-mitotic agent that serves as first line of treatment in metastatic breast cancer, however it is susceptible to cellular drug resistance. Drug-resistant cells are able to spread during treatment, leading to treatment failure and eventually metastasis, which remains the main cause for cancer-associated death. In previous studies, we used single-cell technologies and identified a set of genes that exhibit increased expression in drug-resistant cells, and they are mainly regulated by Lef1. Furthermore, upregulating Lef1 in parental cells caused them to become drug resistant. Therefore, we hypothesized that inhibiting Lef1 could resensitize cells to docetaxel. Here, we confirmed that Lef1 inhibition, especially on treatment with the small molecule quercetin, decreased the expression of Lef1 and resensitized cells to docetaxel. Our results demonstrate that Lef1 inhibition also downregulated ABCG2, Vim, and Cav1 expression and equally decreased Smad-dependent TGF-ß signaling pathway activation. Likewise, these two molecules worked in a synergetic manner, greatly reducing the viability of drug-resistant cells. Prior studies in phase I clinical trials have already shown that quercetin can be safely administered to patients. Therefore, the use of quercetin as an adjuvant treatment in addition to docetaxel for the treatment of breast cancer may be a promising therapeutic approach.

CD44s Induces miR-629-3p Expression in Association with Cisplatin Resistance in Head and Neck Cancer Cells.

Cisplatin (cis-diamminedichloroplatinum II [CDDP] ) is a well-known chemotherapeutic drug that has been used for the treatment of various types of human cancers, including head and neck cancer. Cisplatin exerts anticancer effects by causing DNA damage, replication defects, transcriptional inhibition, cell cycle arrest, and the induction of apoptosis. However, drug resistance is one of the most serious problems with cancer chemotherapy, and it causes expected therapeutic effects to not always be achieved. Here, we analyzed global microRNA (miRNA) expression in CD44 standard form (CD44s)-expressing SAS cells, and we identified miR-629-3p as being responsible for acquiring anticancer drug resistance in head and neck cancer. The introduction of miR-629-3p expression inhibited apoptotic cell death under cisplatin treatment conditions, and it promoted cell migration. Among the computationally predicted target genes of miR-629-3p, we found that a number of gene expressions were suppressed by the transfection with miR-629-3p. Using a xenografting model, we showed that miR-629-3p conferred cisplatin resistance to SAS cells. Clinically, increased miR-629-3p expression tended to be associated with decreased survival in head and neck cancer patients. In conclusion, our data suggest that the increased expression of miR-629-3p provides a mechanism of cisplatin resistance in head and neck cancer and may serve as a therapeutic target to reverse chemotherapy resistance.

Cell-type specific tumorigenesis with Ras oncogenes in human lung epithelial cells.

The oncogenic Ras mutation is one of the most common genomic abnormalities having the highest incidence in cancer; it has three isoforms: Hras, Kras, and Nras. Although the Ras isoforms are highly similar in the primary sequence, each mutational frequency is clearly distinct according to tissue- or cell-type. Regarding non-small-cell lung carcinoma, almost all Kras mutations have been detected in lung adenocarcinoma, whereas lung squamous cell carcinoma is extremely rare. Here, we focus on the cell-type specific tumorigenesis of mutant Ras isoforms and determine the mechanisms of oncogenic signaling outputs between lung adenocarcinoma and squamous cell carcinoma. An in vitro transformation model with mutant Ras isoforms in immortalized bronchial epithelial cells (BEC-E6E7/myc) and immortalized small airway epithelial cells (SAEC-E6E7/myc) revealed that only the HrasG12V mutation, not the KrasG12V mutation, could induce tumorigenesis in BEC-E6E7/myc. In contrast, SAEC-E6E7/myc showed high sensitivity to the KrasG12V mutation compared with the HrasG12V mutation. The transformation of BEC-E6E7/myc and SAEC-E6E7/myc with mutant Ras isoforms was confirmed by soft agar assay and migration assay. HrasG12V-expressing BEC-E6E7/myc significantly increased MAPK/ERK signaling, whereas PI3K/AKT signaling was significantly elevated in KrasG12V-expressing SAEC-E6E7/myc. These results suggest a context dependency with oncogenic Ras mutations in tumorigenesis between lung adenocarcinoma and squamous cell carcinoma.

SMARCA4 deficiency-associated heterochromatin induces intrinsic DNA replication stress and susceptibility to ATR inhibition in lung adenocarcinoma.

The SWI/SNF chromatin remodeling complex regulates transcription through the control of chromatin structure and is increasingly thought to play an important role in human cancer. Lung adenocarcinoma (LADC) patients frequently harbor mutations in SMARCA4, a core component of this multisubunit complex. Most of these mutations are loss-of-function mutations, which disrupt critical functions in the regulation of chromatin architecture and can cause DNA replication stress. This study reports that LADC cells deficient in SMARCA4 showed increased DNA replication stress and greater sensitivity to the ATR inhibitor (ATRi) in vitro and in vivo. Mechanistically, loss of SMARCA4 increased heterochromatin formation, resulting in stalled forks, a typical DNA replication stress. In the absence of SMARCA4, severe ATRi-induced single-stranded DNA, which caused replication catastrophe, was generated on nascent DNA near the reversed forks around heterochromatin in an Mre11-dependent manner. Thus, loss of SMARCA4 confers susceptibility to ATRi, both by increasing heterochromatin-associated replication stress and by allowing Mre11 to destabilize reversed forks. These two mechanisms synergistically increase susceptibility of SMARCA4-deficient LADC cells to ATRi. These results provide a preclinical basis for assessing SMARCA4 defects as a biomarker of ATRi efficacy.

Single-Cell Analysis Reveals a Preexisting Drug-Resistant Subpopulation in the Luminal Breast Cancer Subtype.

Drug resistance is a major obstacle in the treatment of breast cancer. Surviving cells lead to tumor recurrence and metastasis, which remains the main cause of cancer-related mortality. Breast cancer is also highly heterogeneous, which hinders the identification of individual cells with the capacity to survive anticancer treatment. To address this, we performed extensive single-cell gene-expression profiling of the luminal-type breast cancer cell line MCF7 and its derivatives, including docetaxel-resistant cells. Upregulation of epithelial-to-mesenchymal transition and stemness-related genes and downregulation of cell-cycle-related genes, which were mainly regulated by LEF1, were observed in the drug-resistant cells. Interestingly, a small number of cells in the parental population exhibited a gene-expression profile similar to that of the drug-resistant cells, indicating that the untreated parental cells already contained a rare subpopulation of stem-like cells with an inherent predisposition toward docetaxel resistance. Our data suggest that during chemotherapy, this population may be positively selected, leading to treatment failure. SIGNIFICANCE: This study highlights the role of breast cancer intratumor heterogeneity in drug resistance at a single-cell level.

Cancer extracellular vesicles contribute to stromal heterogeneity by inducing chemokines in cancer-associated fibroblasts.

Cancer-associated fibroblasts (CAFs), one of the major components of a tumour microenvironment, comprise heterogeneous populations involved in tumour progression. However, it remains obscure how CAF heterogeneity is governed by cancer cells. Here, we show that cancer extracellular vesicles (EVs) induce a series of chemokines in activated fibroblasts and contribute to the formation of the heterogeneity. In a xenograft model of diffuse-type gastric cancer, we showed two distinct fibroblast subpopulations with alpha-smooth muscle actin (α-SMA) expression or chemokine expression. MicroRNAs (miRNAs) profiling of the EVs and the transfection experiment suggested that several miRNAs played a role in the induction of chemokines such as CXCL1 and CXCL8 in fibroblasts, but not for the myofibroblastic differentiation. Clinically, aberrant activation of CXCL1 and CXCL8 in CAFs correlated with poorer survival in gastric cancer patients. Thus, this link between chemokine expression in CAFs and tumour progression may provide novel targets for anticancer therapy.

Drug library screen reveals benzimidazole derivatives as selective cytotoxic agents for KRAS-mutant lung cancer.

KRAS is one of the most frequently mutated oncogenes in human non-small cell lung cancer (NSCLC). Mutations in KRAS are detected in 30% of NSCLC cases, with most of them occurring in codons 12 and 13 and less commonly in others. Despite intense efforts to develop drugs targeting mutant KRAS, no effective therapeutic strategies have been successfully tested in clinical trials. Here, we investigated molecular targets for KRAS-activated lung cancer cells using a drug library. A total of 1271 small molecules were screened in KRAS-mutant and wild-type lung cancer cell lines. The screening identified the cytotoxic effects of benzimidazole derivatives on KRAS-mutant lung cancer cells. Treatments with two benzimidazole derivatives, methiazole and fenbendazole-both of which are structurally specific-yielded significant suppression of the RAS-related signaling pathways in KRAS-mutated cells. Moreover, combinatorial therapy with methiazole and trametinib, a MEK inhibitor, induced synergistic effects in KRAS-mutant lung cancer cells. Our study demonstrates that these benzimidazole derivatives play an important role in suppressing KRAS-mutant lung cancer cells, thus offering a novel combinatorial therapeutic approach against such cancer cells.

Synthetic Lethality in Lung Cancer-From the Perspective of Cancer Genomics.

Cancer is a genetic disease, and this concept is now widely exploited by both scientists and clinicians to develop new genotype-selective anticancer therapeutics. Although the quest of cancer genomics is in its dawn, recognition of the widespread applicability of genetic interactions with biological processes of tumorigenesis is propelling research throughout academic fields. Lung cancer is the most common cause of cancer death worldwide, with an estimated 1.6 million deaths each year. Despite the development of targeted therapies that inhibit oncogenic mutations of lung cancer cases, continued research into new therapeutic approaches is required for untreatable lung cancer patients, and the development of therapeutic modalities has proven elusive. The "synthetic lethal" approach holds the promise of delivering a therapeutic regimen that preferentially targets malignant cells while sparing normal cells. We highlight the potential challenges in synthetic lethal anticancer therapeutics that target untreatable genetic alterations in lung cancer. We also discuss both challenges and opportunities regarding the application of new synthetic lethal interactions in lung cancer.

Mucosa-associated lymphoid tissue lymphoma with metachronous involvement of the palpebral conjunctiva and bronchus: A case report.

A 61-year-old woman with a history of palpebral conjunctival mucosa-associated lymphoid tissue (MALT) lymphoma, treated with rituximab, was referred to the authors' hospital after follow-up positron emission tomography/computed tomography revealed 18F-fluoro-2-deoxy-d-glucose uptake in a tumor located in the left main bronchus. The diagnosis of MALT lymphoma was made by pathological and immunohistochemical findings homologous to previous palpebral conjunctival lesion via bronchoscopic biopsy. The disease was controlled with rituximab, cyclophosphamide, oncovin, and prednisolone (i.e., R-COP) chemotherapy. Although MALT lymphoma occurs in several organs, metachronous occurrence in the palpebral conjunctiva and bronchus is especially rare, and careful check-up is required to monitor for occurrence of systemic relapse.

Pulmonary Hypertension Exacerbated by Nintedanib Administration for Idiopathic Pulmonary Fibrosis.

The patient was a 71-year-old man with severe idiopathic pulmonary fibrosis (IPF) and who demonstrated a slow deterioration of his respiratory condition. After nintedanib administration, his forced vital capacity and chest high-resolution computed tomography (HRCT) findings were stable, but his dyspnea on exertion were worsened. He was diagnosed with pulmonary hypertension (PH) by right heart catheterization (mean pulmonary arterial pressure: 30 mmHg). In this case, we suspected that nintedanib caused his PH, as his IPF had not progressed.

Vildagliptin ameliorates pulmonary fibrosis in lipopolysaccharide-induced lung injury by inhibiting endothelial-to-mesenchymal transition.

BACKGROUND: Pulmonary fibrosis is a late manifestation of acute respiratory distress syndrome (ARDS). Sepsis is a major cause of ARDS, and its pathogenesis includes endotoxin-induced vascular injury. Recently, endothelial-to-mesenchymal transition (EndMT) was shown to play an important role in pulmonary fibrosis. On the other hand, dipeptidyl peptidase (DPP)-4 was reported to improve vascular dysfunction in an experimental sepsis model, although whether DPP-4 affects EndMT and fibrosis initiation during lipopolysaccharide (LPS)-induced lung injury is unclear. The aim of this study was to investigate the anti-EndMT effects of the DPP-4 inhibitor vildagliptin in pulmonary fibrosis after systemic endotoxemic injury. METHODS: A septic lung injury model was established by intraperitoneal injection of lipopolysaccharide (LPS) in eight-week-old male mice (5 mg/kg for five consecutive days). The mice were then treated with vehicle or vildagliptin (intraperitoneally, 10 mg/kg, once daily for 14 consecutive days from 1 day before the first administration of LPS.). Flow cytometry, immunohistochemical staining, and quantitative polymerase chain reaction (qPCR) analysis was used to assess cell dynamics and EndMT function in lung samples from the mice. RESULTS: Lung tissue samples from treated mice revealed obvious inflammatory reactions and typical interstitial fibrosis 2 days and 28 days after LPS challenge. Quantitative flow cytometric analysis showed that the number of pulmonary vascular endothelial cells (PVECs) expressing alpha-smooth muscle actin (α-SMA) or S100 calcium-binding protein A4 (S100A4) increased 28 days after LPS challenge. Similar increases in expression were also confirmed by qPCR of mRNA from isolated PVECs. EndMT cells had higher proliferative activity and migration activity than mesenchymal cells. All of these changes were alleviated by intraperitoneal injection of vildagliptin. Interestingly, vildagliptin and linagliptin significantly attenuated EndMT in the absence of immune cells or GLP-1. CONCLUSIONS: Inhibiting DPP-4 signaling by vildagliptin could ameliorate pulmonary fibrosis by downregulating EndMT in systemic LPS-induced lung injury.

Choroidal metastasis of non-small cell lung cancer that responded to gefitinib.

A 52-year-old Japanese woman presented with optical symptoms, including left-sided myodesopsia, blurred vision, narrowed visual field, and diminished visual acuity. Ocular evaluation revealed a metastatic tumor in the choroid. Further examinations identified pulmonary adenocarcinoma as the primary tumor. Because an epidermal growth factor receptor gene (EGFR) mutation was detected in a biopsy specimen, gefitinib treatment was initiated. Dramatic responses were obtained in the primary tumor and metastatic foci. Optical symptoms improved and remained stable for 5 months during the treatment, until relapse. This report demonstrates that gefitinib is effective for choroidal metastasis of pulmonary adenocarcinoma harboring an EGFR mutation.